@MappedSuperclass
public abstract class BaseEntityObject {
  private Integer myInt;

  @Column(name = "SOME_COLUMN")
  public Integer getSomeColumn() {
    return myInt;
  }

  public void setSomeColumn(Integer value) {
    myInt = value;
  }
}

...
@Entity
public class EntityA extends BaseEntityObject {
  private Integer myOverridingInt;

  @Column(name = "SOME_COLUMN")
  public Integer getSomeColumn() {
    return myOverridingInt;
  }

  public void setSomeColumn(Integer value) {
    myOverridingInt = value;
  }
}

@Entity
public class EntityB extends BaseEntityObject {
}